Last modified: 2014-06-30 11:14:14 UTC
There is a '@todo: add drop patch with 1.24' in tables.sql (added by Skizzerz in f7174057a4ec7b9c74babfe74290bb000204a581). Someone please do this. This field also exists for some other DBMSs (which even have some schema updates defined for it), but not MySQL.
todo was in tables.sql at that time, so that was only a copy. Field was removed with Gerrit change #125769 for mysql. Other databases needs follow up from developer with that dbms to test the drop patch.